Improvement in printing-telegraphs



T. A. EDISON.

Improvement in Printing-Telegraph's,

No.-i28,60 7.

Patented July 2,1872.

. Mr. F/IG To wrws RI awaca. 4 r. fasaamgs F/OCA? s) i TED STATES ATETHOMAS A. EDISON, OF NEWARK, NEW JERSEY.

Specification forming part of Letters Patent No. 128,607, dated July 2,1872.

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, of Newark, in the countyof Essexand State of New Jersey, have invented an Improvement inPrinting-Telegraphs; and the following is declared to be a correctdescription of the same.

In this instrument the magnet that gives the impression is in themain-line circuit as well as the type-wheel magnet, but the former iscut out by a shunt or short circuit that is closed when the instrumentis not working, and during the pulsations that set the typewheel; butwhen a pause occurs with the circuit closed this short circuit is brokenby a gradually-operatin g spring or weight controlled by an air-cushion,so that the electricity is forced to pass through the printing-magnetand gives the impression, simply in consequence of keeping the circuitclosed when the letter to be printed has arrived in position for theimpression. I

In the drawing, Figure l is a plan, and Fig. 2 an elevation, of theinstrument.

The finger-key a is introduced to illustrate any suitable apparatus foropening and closing the electric circuit from the battery I). 1represents the line-wire, and 2 the ground or return circuit. Thetype-wheel c is moved by any suitable step-by-step motion. I have shownthe ratchet-wheel d and lever e, operated by the armature f and spring4. The printing-lever 9 may also be of any desired character. Thetype-wheel magnet h is connected with the line-wirel, and from this thewire 5 leads to the printing-magnet t, and thence the circuit returns bythe wire 2. If this alone was used, both magnets would be energized eachpulsation 5 therefore, to prevent this, I employ the short circuit orshunt, composed of the wire 7 leading to the screw i, and the wire 9leading to the tongue 0. The air-cushion is made of the cylinder n,within which is a piston, and

the rod '1" of the same rests at its lower end upon the tongue 0, andthe parts are adjusted so that the circuit between i and 0 is closedwhen the parts are at rest, because a collar, 3, on the rod 1' restsupon the type-wheel lever e and holds the rod 7' up against the springu.

When the type-wheel leveny'is vibrated in setting the type-wheel, themovement is sufficiently rapid to keep pressing the rod 7' up againstthe action of the spring u, and the aircushion prevents its return withrapidity; but when a pause takes place in the pulsations, and thecircuit is kept closed, the rod 1 descends and moves the tongue 0,breaking the shunt-circuit through 7, i, 0, and 9, and compelling theelectricity to pass through the magnet 17 and produce the printing. Theparts return to the position of inactivity with magnet t cut out by thecircuit 7 'i o 9, when the circuit is broken at the transmittingstation, and I remark that there might be a finger upon theprinting-lever g to lift the rod 1", in which case the impression-leverwould drop back instantly, as the circuit would be closed again through7, t, o, and 9; and in this manner a second or third impression of thesame letter, number, or character would be given by keeping the circuitclosed at the transmitting station to allow sufficient time for the rod1" to descend again and open the shunt at 0 t.

I claim as my invention- Two electro-magnets, one for operating thetype-wheel lever, the other for giving the im- 'pression, both in themain circuit, in combination with a shunt or cut-out circuit and ashunt-breaker, substantially as and for the purposes set forth.

Signed by me this 26th day of April, A. D.

T. A. EDISON. Witnesses:

Gno. T. PINcKNEY, Ones. 11. SMI'rn.

